In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed...In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.展开更多
Integrated agronomic practice management(IAPM)is an effective strategy for increasing nitrogen(N)use efficiency(NUE)and yield during crop production.Although various studies have evaluated the mechanism of a single ag...Integrated agronomic practice management(IAPM)is an effective strategy for increasing nitrogen(N)use efficiency(NUE)and yield during crop production.Although various studies have evaluated the mechanism of a single agronomic management practice to increase yield and production efficiency and decrease environmental costs,few have investigated the effects of IAPM systems.A field experiment was conducted using four IAPM systems,a local smallholder farmers’practice system(T1),an improved management system(T2),a high-yield production system(T3),and an optimized management system(OMS),to study the annual yield,greenhouse gas(GHG)emissions,carbon(C)footprint(CF),and net environmental ecological benefit(NEEB)of summer maize.The results revealed that OMS was the most advantageous choice of IAPM,which increased yield and NUE and reduced GHG emissions and CF.Under OMS,yield and NUE were 42.6%and 88.1%higher,and N_(2)O,CO_(2),and CH4 emissions were on average 35.4%,5.8%,and 156.5%lower,respectively,than those under T1.Of the four IAPM systems,OMS resulted in the best soil quality,the lowest soil bulk density,the highest soil C/N ratio,and the highest soil total organic C content,which contributed to reduced GHG emissions.Carbon footprint and cost were the lowest under OMS,which decreased fertilizer input and GHG emissions.Optimized management system reduced CF and C cost by 5.9%and 33.9%,respectively,and increased NEEB by 111.4%compared to T1.Although T3 had the highest yield,it also had the highest GHG emissions and CF.In conclusion,OMS delivered a high yield and NUE while mitigating negative environmental impacts and increasing NEEB.Therefore,OMS is a suitable management system to increase the productivity and sustainability of summer maize.展开更多
超音速分离技术是一种集低温制冷及气液分离于一体的新技术,2011年6月,国内引进的首套超音速分离器(super sonic separator,3S)在中国石油塔里木油田公司牙哈作业区凝析气处理厂投产成功。为此,介绍了超音速分离器的工作原理及脱油脱水...超音速分离技术是一种集低温制冷及气液分离于一体的新技术,2011年6月,国内引进的首套超音速分离器(super sonic separator,3S)在中国石油塔里木油田公司牙哈作业区凝析气处理厂投产成功。为此,介绍了超音速分离器的工作原理及脱油脱水工艺流程。运行效果表明,相对于传统制冷(如J-T阀、冷剂和膨胀机制冷)设备,超音速分离器具有以下优势:①效率高。发生在超音速喷管中的膨胀降压、降温、增速过程以及发生在扩散器中的减速、升压、升温过程,均为气体的内部能量转换过程,经过全面优化设计,能使能量损失降低到最低限度。②能耗低。与低温法丙烷制冷相比,在凝液收率相同的情况下,3S可减少制冷压缩机电耗50%～70%;而3S代替膨胀机,在凝液收率相同的情况下,可多回收15%～20%的压缩功率。③无转动部件、属静设备,因此运行更加安全可靠。④工艺过程和设备简单,投资省。⑤本身无消耗,无须水、电、仪表风的支持,除了温度和压力的监控,不依赖控制系统,运行成本低。⑥无废水、废液排出,对环境无影响。⑦体积小,占地和占有的空间小。超音速分离器可以更深度地脱水脱油,从而提高商品天然气品质,并可增加凝液产量,同时明显降低能耗,获得更好的经济效益。展开更多
文摘In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.
基金funded by China Agriculture Research System of Ministry of Finance and Ministry of Agriculture and Rural Affairs and the National Key and Development Program of China(No.2017YFD0300304).
文摘Integrated agronomic practice management(IAPM)is an effective strategy for increasing nitrogen(N)use efficiency(NUE)and yield during crop production.Although various studies have evaluated the mechanism of a single agronomic management practice to increase yield and production efficiency and decrease environmental costs,few have investigated the effects of IAPM systems.A field experiment was conducted using four IAPM systems,a local smallholder farmers’practice system(T1),an improved management system(T2),a high-yield production system(T3),and an optimized management system(OMS),to study the annual yield,greenhouse gas(GHG)emissions,carbon(C)footprint(CF),and net environmental ecological benefit(NEEB)of summer maize.The results revealed that OMS was the most advantageous choice of IAPM,which increased yield and NUE and reduced GHG emissions and CF.Under OMS,yield and NUE were 42.6%and 88.1%higher,and N_(2)O,CO_(2),and CH4 emissions were on average 35.4%,5.8%,and 156.5%lower,respectively,than those under T1.Of the four IAPM systems,OMS resulted in the best soil quality,the lowest soil bulk density,the highest soil C/N ratio,and the highest soil total organic C content,which contributed to reduced GHG emissions.Carbon footprint and cost were the lowest under OMS,which decreased fertilizer input and GHG emissions.Optimized management system reduced CF and C cost by 5.9%and 33.9%,respectively,and increased NEEB by 111.4%compared to T1.Although T3 had the highest yield,it also had the highest GHG emissions and CF.In conclusion,OMS delivered a high yield and NUE while mitigating negative environmental impacts and increasing NEEB.Therefore,OMS is a suitable management system to increase the productivity and sustainability of summer maize.
文摘超音速分离技术是一种集低温制冷及气液分离于一体的新技术,2011年6月,国内引进的首套超音速分离器(super sonic separator,3S)在中国石油塔里木油田公司牙哈作业区凝析气处理厂投产成功。为此,介绍了超音速分离器的工作原理及脱油脱水工艺流程。运行效果表明,相对于传统制冷(如J-T阀、冷剂和膨胀机制冷)设备,超音速分离器具有以下优势:①效率高。发生在超音速喷管中的膨胀降压、降温、增速过程以及发生在扩散器中的减速、升压、升温过程,均为气体的内部能量转换过程,经过全面优化设计,能使能量损失降低到最低限度。②能耗低。与低温法丙烷制冷相比,在凝液收率相同的情况下,3S可减少制冷压缩机电耗50%～70%;而3S代替膨胀机,在凝液收率相同的情况下,可多回收15%～20%的压缩功率。③无转动部件、属静设备,因此运行更加安全可靠。④工艺过程和设备简单,投资省。⑤本身无消耗,无须水、电、仪表风的支持,除了温度和压力的监控,不依赖控制系统,运行成本低。⑥无废水、废液排出,对环境无影响。⑦体积小,占地和占有的空间小。超音速分离器可以更深度地脱水脱油,从而提高商品天然气品质,并可增加凝液产量,同时明显降低能耗,获得更好的经济效益。
